Researchers from the Scripps Institution of Oceanography at the University of California-San Diego and Yale University found that rising temperatures in the Indian Ocean can help boost the Atlantic meridional overturning circulation(AMOC) and delay slow down.
How does warming of the Indian Ocean affect AMOC?
What is AMOC? ● It is sometimes referred to as the “Atlantic conveyor belt”, is one of the Earth’s largest water circulation systems where ocean currents move warm, salty water from the tropics to regions further north, such as western Europe and sends colder water south. ● It aids in distributing heat and energy around the earth, as the warm water it carries releases heat into the atmosphere, and in absorbing and storing atmospheric carbon. ● For thousands of years, AMOC has remained stable, but since the past 15 years, it has been weakening, a development that could have dramatic consequences for Europe and other parts of the Atlantic rim, according to a study published in the journal Nature Climate Change.
What lies ahead?
- Warming in the Indian Ocean generates additional precipitation which results in drawing more air from other parts of the world, including the Atlantic.
- The higher level of precipitation in the Indian Ocean will reduce precipitation in the Atlantic and increase salinity in the waters.
- This saline water in the Atlantic, as it comes north through AMOC, will get cold much quicker than usual and sink faster, acting as a jump start for AMOC, intensifying the circulation.
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- No one knows how long this enhanced warming in Indian Ocean will continue.
- If other tropical oceans, especially the Pacific Ocean starts warming at a similar rate as the Indian Ocean, the advantage for AMOC will stop.
- Also, it is not clear if the slowdown of AMOC is due to global warming alone or it is a short-term anomaly related to natural ocean variability.
- There is a need to understand the importance of AMOC stability.
- AMOC last witnessed a slow down 15,000 to 17,000 years ago and it caused harsh winters in Europe, with more storms or a drier Sahel in Africa due to the downward shift of the tropical rain belt.
- The finding exemplifies the intricate, interconnected nature of global climate.